If it were me, i,d have an Ecutek done, Turbo back exhaust, clutch AND some brakes and if enough left over a nice suspension upgrade.

I,ve had 5 Evos...Lol, ok you,ll not make dead-on your 400 target, but it,ll be bloody close and with brakes, suspension it,ll be a hoot of a car.

Mine made 387bhp/381ft/lb when Ecuteked, made 480/460 after a MA Developments build mind you....